Finish the hard parts of the lua makeover

- bundle luarocks source in the panto binary
- bootstrap process (intended for first `panto` run):
  - make ~/.local/share/panto/...
  - write out luarocks sources into it
  - run luarocks to install luv
- new `panto bootstrap` command just runs the bootstrap
- `panto bootstrap --force` removes everything and re-bootstraps
- new `panto lua` command just runs panto's embedded lua

1 files changed, 68 insertions, 0 deletions

diff --git a/build/gen_lua_headers_embed.zig b/build/gen_lua_headers_embed.zig
new file mode 100644
index 0000000..1ac4004
--- /dev/null
+++ b/build/gen_lua_headers_embed.zig
@@ -0,0 +1,68 @@
+//! Build-time codegen: emit a Zig module exposing every Lua public
+//! header from the Lua source tarball as embedded bytes. Bootstrap
+//! writes these to `$PANTO_HOME/rocks/lua-X.Y.Z/include/` on first run
+//! so luarocks can compile C rocks against them.
+//!
+//! Invoked from `build.zig`:
+//!
+//!     gen-lua-headers-embed <lua-src-dir> <out-file>
+//!
+//! `<lua-src-dir>` is the `src/` directory of the Lua tarball.
+
+const std = @import("std");
+
+const headers = [_][]const u8{
+    "lua.h",
+    "luaconf.h",
+    "lualib.h",
+    "lauxlib.h",
+    // hpp is the C++-friendly include shim shipped upstream; some C
+    // rocks reference it.
+    "lua.hpp",
+};
+
+pub fn main(init: std.process.Init) !void {
+    const arena = init.arena.allocator();
+    const io = init.io;
+
+    var args = init.minimal.args.iterate();
+    defer args.deinit();
+    _ = args.next();
+    const embed_prefix = args.next() orelse return error.MissingEmbedPrefix;
+    const src_dir = args.next() orelse return error.MissingSrcDir;
+    const out_path = args.next() orelse return error.MissingOutPath;
+
+    var out_file = try std.Io.Dir.cwd().createFile(io, out_path, .{});
+    defer out_file.close(io);
+    var buf: [4096]u8 = undefined;
+    var writer = out_file.writer(io, &buf);
+    const w = &writer.interface;
+
+    try w.writeAll(
+        \\//! Auto-generated. Do not edit. See build/gen_lua_headers_embed.zig.
+        \\
+        \\pub const Entry = struct {
+        \\    name: []const u8,
+        \\    contents: []const u8,
+        \\};
+        \\
+        \\pub const files: []const Entry = &.{
+        \\
+    );
+
+    for (headers) |name| {
+        const abs = try std.fs.path.join(arena, &.{ src_dir, name });
+        // Verify the file exists; emit nothing for missing files (lua.hpp
+        // exists in current Lua releases but we don't want to hard-fail
+        // if the tarball ever drops it).
+        std.Io.Dir.cwd().access(io, abs, .{}) catch continue;
+        const embed_path = try std.fs.path.join(arena, &.{ embed_prefix, name });
+        try w.print(
+            "    .{{ .name = \"{s}\", .contents = @embedFile(\"{s}\") }},\n",
+            .{ name, embed_path },
+        );
+    }
+
+    try w.writeAll("};\n");
+    try w.flush();
+}